If the customer has the old Kaseya 2 Addin installed
Copy the attached AuthAnvilKaseyaAddIn.dll to your Kserver specifically into "c:\Kaseya\WebPages\bin\".
(If you have any problems accessing the attached DLL log into https://kaseya.zendesk.com and you will be able to download it from the case directly).
Next run the Addin installer http://storage.scorpionsoft.com/apps/aapsfk/4/2/0/AuthAnvilPasswordSolutionsForKaseya.exe
The upgrade should not have the issues with the Schema rebuild at all.